Outline

Introduction: Chemotherapy in young women with cancer has improved life expectancy in these patients, but this treatment often causes infertility. In the past decade, there has been a surge of interest in fertility preservation for these patients. Among the most promising technologies for young women is the strategy of cryopreserving ovarian cortical tissue for subsequent reimplantation. The feasibility of this procedure was proven by the birth of the first child after retransplantion of cryopreserved ovarian tissue to its mother in Brussels 2004. This event increased the amount of requests for cryopreservation of ovarian tissue for patients facing cytotoxic anticancer treatment.

Aim of this study: To evaluate a cryopreservation protocol in an open freezing system.

Material and Methods: Ovarian tissue was obtained from mice, rats and premenopausal women. Tissue was dissected into cubes of about 1 mmÂ² and frozen in straws containing a combination of DMSO and Propanediol. Cryopreservation was performed using an open freezing system (CTE, HÃ¶chstadt, Germany) and a long protocol. Frozen-thawed tissue from mice and rats was isografted into the neck of animals of the same inbred strain; human tissue was xenotransplanted to SCID-mice. After killing, recovered grafts were entirely serially sectioned for histological evaluation and the number of follicles of the different samples was counted.

Conclusion: The development of follicles in all grafts of three species demonstrates that the open freezing system allows also the good preservation of human ovarian cortex. Although freezing diminishes the number of follicles it does not affect the ability of follicles to proceed to antral stages. Until now ovarian tissue of 82 patients have been frozen by this method and stored for further use in the cryobank of the OB/GYN of the University-Hospital Erlangen.